1. Field of the Disclosure
The present disclosure generally relates to the field of heat exchangers including aluminum heat exchangers used to cool internal combustion engines.
2. Brief Description of Related Art
Heat exchangers are used to transfer thermal energy from one medium to another. For example, in an internal combustion engine cooling application, heat is transferred from the internal combustion engine to the cooling fluid and the cooling fluid is itself cooled as its heat is transferred to the atmosphere when the coolant flows through a radiator. The coolant flow to and from the radiator may be pumped, and a fan may be provided in the proximity of the radiator to blow air through the radiator. In any event, the coolant flow and corresponding cooling process continues during operation of the internal combustion engine, thereby maintaining the operating temperature of the internal combustion engine within acceptable limits and preventing the engine from overheating.
At present, aluminum radiators are less expensive to manufacture in high volumes than copper or brass radiators, but tend to be less durable. A typical heat exchanger or radiator includes a manifold assembly that conducts fluid flow through a plurality of flow tubes or exposed pipes (often with fins or other means for cooling increasing surface area) to reduce the operating temperature of the internal combustion engine. A manifold assembly typically includes a tank and a header joined together. Furthermore, current aluminum compact heat exchanger designs that use aluminum tanks either require the use of aluminum sidebrackets or secondary machining operations to use steel sidebrackets. The aluminum sidebrackets furthermore tend to lack the strength and cost advantages of the steel sidebrackets that are commonly used on copper and brass radiators.
More particularly, current aluminum compact heat exchanger designs utilize a variety of tanks—plastic tanks, formed tanks, fabricated tanks, or cast tanks. Plastic tanks are mainly used for mass production, but may not be cost effective for production levels below about 100,000 units per year. A formed tank, on the other hand, does not provide for ready assembly to the sidebrackets. Therefore, sidebrackets are generally welded or brazed to the core or the tank and, hence, are often made of aluminum, which is more expensive and weaker than steel. Fabricated tanks may not be cost effective for production quantities over about 500 units per year.
However, current cast tank designs fail in creating an interchangeable tank that has a consistent tank-to-header seam location whenever such a tank is mounted on a header. One reason for such inconsistent tank-to-header seam location is the inconsistent core height growth during the core baking process (i.e., during the fin-to-tube and tube-to-header brazing process). This inconsistent tank-to-header seam location results in variations in tank-to-header welding locations for each tank-header pair and, hence, makes it difficult to use robotic welding to attach the tanks to the headers. Misaligned or improperly seated tanks, furthermore, are undesirable because they can result in leaks after the tank is welded to the header.
Even in the case where aluminum sidebrackets are used, problems could arise when such sidebrackets are welded to the core or tanks of the heat exchanger. Such welded sidebrackets may fail to accommodate thermal expansions (of the core or the tanks) that occur, for example, during welding or brazing or even under normal operating conditions. When no adequate means are provided to accommodate thermally expanding metals, damage to the core may result in the case where such welded aluminum sidebrackets are utilized.
Therefore, it is desirable to provide an all aluminum (or aluminum alloy) industrial heat exchanger (i.e., radiator) that provides consistency in tank-to-header joint locations to better allow for the use of robotic welding to attach tanks to headers.
It is also desirable that a heat exchanger include a cast tank manufactured from aluminum or aluminum alloy and be suitable for robotic welding without the need for machining the tank.
It is further desirable to devise a sidebracket mounting mechanism for a radiator that permits the use of stronger steel sidebrackets on an aluminum core, while allowing for thermal expansion of the core without the need for machining the tank.